relating to Air and Water* 3 ©5 



Willing to try the effed of heating iron, and other fub- 

 flances, in all the different kinds of air, without any particular 

 expectation, I found that iron melted more readily in vitriolic 

 acid air than in dephlogifticated air, the air was diminifhed as 

 rapidly, and the inlide of the veffel was covered with a black 

 footy matter^ which, when expofed to heat, readily fublimed in 

 the form of a white vapour, and left the glafs quite clean. 

 The iron, after the experiment, was quite brittle, and 

 muft, I prefume, be the fame thing with iron that is ful- 

 phurated\ but I did not particularly examine it. Of feven 

 ounce meafures of vitriolic acid air, in one of thefe experi- 

 ments, not more than three-tenths of an ounce meafure re- 

 mained ; of this two-thirds was fixed air, and the refiduum 

 of this was inflammable. I had put three of fuch refiduums 

 together, in order to m.ake the experiment with the greater 

 certainty. 



Having tranfmitted Jleam, or the vapour of water, through 

 a copper tube, I was willing to try the efteds oi fpirit of wifie 

 through the fame tube when red-hot, having before procured 

 inflammable air by fending the fame vapour through a. red- hot- 

 tobacco-pipe. In this cafe, the vapour of the fpirit cf wine 

 had no fooner entered the hot copper tube, than I was perfedly 

 aftonirtied at the rapid produ6tion of air. It refembled the 

 blowing of a pair of bellows. But I had not ufed four ounces, 

 of the fpirit of wine before I very unexpectedly found, that 

 the tube was perforated in feveral places ; and prefently after- 

 wards it was fo far deftroyed, that in attempting to remove it 

 from the nre it adually fell in pieces. The infide waS' full of a 

 black footy matter refembling lamp-black. 



Upon this I had recourfe to earthen tubes, and found, that by 

 melting copper and other metals in them, and tranfmitting the 



Vol. LXXV. R r vapour 



